A general gas turbine is formed of a compressor, a combustor, and a turbine. The compressor compresses air taken in from an air intake port to generate high temperature and high pressure compressed air. By supplying fuel to this compressed air to cause combustion, the combustor obtains high temperature and high pressure combustion gas. The turbine is driven by this combustion gas and drives a generator coaxially connected thereto.
In the turbine, a rotor is driven to rotate, by the high temperature and high pressure combustion gas generated in the combustor passing plural turbine vanes and turbine blades that are present in a combustion gas passage. A sealing apparatus, called a rim seal, is provided, in order to prevent this combustion gas from going into a turbine body from a gap between a turbine blade and a turbine vane. This rim seal prevents the entrance of the combustion gas by supplying purge air to a disc cavity formed in a gap between a turbine blade and a turbine vane, and jetting out the purge air in this disc cavity toward the gap between the turbine blade and the turbine vane. Such rim seals include, for example, a rim seal described in Japanese Unexamined Patent Application Publication No. 2010-077868.